1. Field of the Invention
This invention relates to couplings for hydraulic fluid lines. More particularly, the invention pertains to quickly detachable fluid couplings.
2. Description of the Prior Art
U.S. Pat. No. 4,266,814 describes a fitting for receiving and locking a plastic tube in position. It includes a hollow tubular member having compression barbs and flexible locking barbs for gripping the tube and fixing its position with respect to the adapter. The tube has several locking barbs, which have sharp cornered ends adapted to engage and lock a plastic tube in place. The tube includes a set of compression barbs which engage a beam to clamp the tubing into position. The locking barbs bind the surface of the tubing and prevents disassembly of the adapter. The force required to assemble and disconnect the adapter varies substantially with the temperature of the components and the stiffness of the tubing. This coupling is not suited for use with the large temperature variations of approximately 300 degrees F. to which the radiator hose of an internal combustion is subjected. High temperature softens the plastic tube and lowers the coupling strength. Low temperature stiffens and shrinks the tubing and could cause leakage between the tube and components. There is no positive indication of complete engagement, either visual or audible.
The quickly detachable pipe coupling described in U.S. Pat. No. 3,245,703 include male and female members that are locked together by means of resilient latch fingers on the male member. These latching elements are received on an interior annular recess located on the female member. The assembly of the coupling requires the pressing of two fingers concurrently and then inserting one member within the other until they reach a locking position. The displacement of the finger during assembly requires a radial gap along the male member in order to accommodate the displacement. There is no tendency in the process of assembling this coupling for the coupling members to be forced axially away from one another after the end of the finger clears the edge of the female member. In addition, there is no positive indication of complete engagement because the end of the fingers are not visible once they clear the end face of the female member.